Communication system utilizing information received during a silent interval between ringing signals

Abstract

A communication system detects special service information (e.g., calling party identification) during a silent interval between ringing signals on an incoming call and stores the information in a call record created for the call. In response to predetermined call conditions, this information is included as part of a control signal sent over an extension loop to a station terminal. Call features such as delayed ringing, hold, call transfers, line preselect and switch hook status are utilized to control where, when and if this information should be displayed at various station terminals.

We claim: 
     
       1. A communication system for switchably controlling connections between a plurality of external communication lines and one or more system extension loops which connect to the system; said system comprising table means for associating each of said plurality of lines with at least one extension loop of said system,   means for detecting information in a silent interval between ringing signals of an incoming call received over a first one of said lines,   means for storing said information in a call record established for said call prior to said call being answered,   means responsive to a predetermined call condition at said system for sending at least a portion of said stored information as part of an output control signal sent over an extension loop, and wherein   said system in response to a line identification signal accesses said table means to select at least one extension loop of said one or more extension loops which is to receive said control signal.   
     
     
       2. The system of claim 1 wherein said control signal includes said information portion encoded as a display signal. 
     
     
       3. The system of claim 2 wherein said system sends a clear display signal over said extension loop in response to a input signal received over said extension loop. 
     
     
       4. The system of claim 3 wherein said received input signal from said extension loop indicates a request that an active call on said first line be placed on hold. 
     
     
       5. The system of claim 3 wherein said received input signal from said extension loop indicates a request to transfer an active call on said extension loop. 
     
     
       6. The system of claim 1 wherein when said system has an active call on said extension loops, said system is responsive to a received transfer control signal from said extension loops for transferring said active call to a second extension loop and further is responsive to an off-hook control signal from said second extension loop for sending a display control signal over said second extension loop. 
     
     
       7. The system of claim 1 wherein when said system has an active call on said extension loops, said system is responsive to a received first line pick up control signal followed by an off-hook control signal from a second extension loop for sending a display signal over said second extension loop. 
     
     
       8. A communication system for switchably controlling connections between a plurality of external communication lines and one or more system extension loops which connect to the system; said system comprising means for detecting information in a silent interval between ringing signals of an incoming call received over a first one of said lines,   means for storing said information in a call record established for said call prior to said call being answered,   means responsive to a predetermined call condition at said system for sending at least a portion of said stored information as part of an output control signal sent over an extension loop, and   wherein said call condition is an expiration of a delayed ring state established to delay the sending of a ring control signal, representing said ringing first line, over said extension loop.   
     
     
       9. The system of claim 1 wherein said control signal is used to regenerate an analog ringing signal including said information portion outputted in a silent interval between rings. 
     
     
       10. A method of operating a communication system for switchably controlling connections between a plurality of external communication lines and one or more system extension loops which connect thereto; said method comprising the steps of detecting information in a silent interval between ringing signals of an incoming call received over a first one of said lines,   storing said information in a call record established for said call prior to said call being answered,   in response to a predetermined call condition at said system, sending at least a portion of said stored information as part of a control signal sent over an extension loop, and   wherein said call condition is an expiration of a delayed ring state established to delay the sending of a ring control signal representing said ringing first line over said extension loops.   
     
     
       11. A method of operating a communication system for switchably controlling connections between a plurality of external communication lines and one or more system extension loops which connect thereto; said method comprising the steps of associating each of said plurality of lines with at least one extension loop of said system in a table means,   detecting information in a silent interval between ringing signals of an incoming call received over a first one of said lines,   storing said information in a call record established for said call prior to said call being answered,   in response to a predetermined call condition at said system, sending at least a portion of said stored information as part of a control signal sent over an extension loop, and   in response to a line identification signal, accessing said table means to select at least one extension loop of said one or more extension loops which is to receive said control signal.   
     
     
       12. The method of claim 11 wherein said control signal includes said information portion encoded as a display signal. 
     
     
       13. The method of claim 12 further including the step of in response to a control signal received over said extension loops, sending a clear display signal over said extension loops.   
     
     
       14. The method of claim 13 wherein said received control signal from said extension loops indicates a request that an active call on said first line be placed on hold. 
     
     
       15. The method of claim 13 wherein said received control signal from said extension loops indicates a request to transfer an active call on said extension loops to another extension loop. 
     
     
       16. The method of claim 11 further including the steps of in response to an active call on said extension loops and to a received transfer control signal from said extension loops,   transferring said active call to a second extension loop and   in response to an off-hook control signal from said second extension loop, sending a display control signal over said second extension loop.   
     
     
       17. The method of claim 11 further including the step of in response to an active call on said first line and to a received first line pick up control signal followed by an off-hook control signal from a first extension loop, sending a display signal over said first extension loop.   
     
     
       18. The method of claim 11 wherein said control signal is a system generated analog ringing signal including said information portion outputted in a silent interval between rings. 
     
     
       19. A communication system, including a controller, for switchably controlling connections between a plurality of external communication lines and one or more station terminals which connect thereto over extension loops, said system comprising at said controller,   table means for associating each of said plurality of lines with at least one extension loop of said system,   means for detecting information in a silent interval between ringing signals of an incoming call received over a first one of said lines,   means for storing said information in a call record established for said call prior to said call being answered,   means responsive to a predetermined call condition at said system for sending at least a portion of said stored information as part of an output control signal sent over an extension loop to a station terminal, and wherein   said system, in response to a line identification signal, accesses said table means to select at least one extension loop of said one or more extension loops which is to receive said control signal, and   said station terminal including means for receiving and displaying said information portion of a received output control signal.   
     
     
       20. The system of claim 19 wherein said station terminal is a digital station terminal having display means and said control signal includes said information portion sent as a display signal for display at said digital display station terminal. 
     
     
       21. The system of claim 19 wherein said terminal is an analog station terminal and said controller regenerates an analog ringing signal, including said information portion outputting in a silent interval between rings, which is sent to said analog station terminal.